An upgraded wildfire warning has been issued for Northern Ireland as a heatwave with temperatures close to 30C takes hold in the coming days.

A yellow alert from the National Hazards Partnership has been upgraded to an amber warning for Saturday and Sunday, indicating a likelihood of difficult to control wildfires.

A combination of dry vegetation and sunny, warm weather creates ideal conditions for wildfires to take hold.

In April, the Northern Ireland Fire and Rescue service dealt with almost 150 wildfires, mainly in County Down.

The organisation previously urged people to enjoy the weather responsibly during a similar wildfire warning in April.

While tens of thousands of people are expected enjoy the very warm spell during Twelfth demonstrations, the Tyrone and Donegal GAA semi-finals at Croke Park, and at beaches and parks, there are also alerts for high levels of UV and pollen, as well as a rise in pollution.

Hay fever sufferers will have to endure high grass pollen levels until Sunday, with moderate weed pollen levels also forecast.

Pollution levels are set to rise during the settled spell, with moderate levels expected in eastern areas on Saturday and Sunday, while protection from the harmful rays of the sun is also advised as high levels of UV are forecast.

Temperatures on Wednesday and Thursday reached 25C in parts of Northern Ireland and they are set to be higher in places on Friday, approaching 30C on Saturday and Sunday.

For a heatwave to be declared temperatures must reach 25C or above for at least three consecutives days, according to the Met Office.

The average maximum daytime temperature at this time of year is 18.6C in Northern Ireland.

Other parts of the UK have different temperature thresholds to reach in the same amount of time, while in the Republic of Ireland a temperature of 25C must be recorded for at least five days, according to the Irish Meteorological Service, Met Éireann.

High temperature warnings have been issued across the Republic of Ireland, where daytime temperatures are forecast to exceed 27C by day, with overnight lows staying above 15C.

The first warning, affecting 14 midland and eastern counties, comes into effect from midday on Friday until 06:00 local time on Saturday, with a second warning expanding to cover all of the Republic from midday on Saturday until 06:00 on Sunday.

Another warning has been issued from midday on Sunday until 18:00. It affects counties Carlow, Cavan, Clare, Donegal, Galway, Kildare, Kilkenny, Leitrim, Laois, Limerick, Longford, Mayo, Offaly, Roscommon, Sligo, Tipperary, and Westmeath.

Water authorities in both Northern Ireland and the Republic of Ireland have urged members of the public to conserve water during the warm spell.

NI Water have expressed concern that “high temperatures can create a huge demand surge” for water.

Speaking to BBC News NI, Maynard Cousley of NI Water, said: “Reservoirs are in reasonable shape for the second week of July, but after a few days of temperatures in their low to mid 20s, we see a sudden rise in demand and that puts pressure on our whole distribution network.

“We have people working around the clock to keep people in water and that’s what we aim to do.”

He added that there has been a rise in demand over the last 24 hours and asked people to “be careful with the water they are using this weekend”.

“At this stage we have no plans to introduce a hosepipe ban,” he said.

On Thursday, Uisce Éireann in the Republic of Ireland issued an appeal to conserve amid an ongoing hosepipe ban in County Westmeath.

The organisations are urging everyone to take steps such as using a watering can instead of hoses, shortening showers, and turning off taps while brushing teeth.