The club will join northern rivals Launceston City and Devonport City to stand out of their opener over Football Tasmania's heat policy.

A forecasted high of 37 degrees in Hobart has forced the scheduled triple-header at KGV Park to be scrapped, but not Friday night's opener between Olympic Warriors and South Hobart.

Riverside was set to meet Clarence United and City to face Kingborough Lions.

Football Tasmania now plans to delay the round-one fixtures until Easter Monday.

FT chief executive Matt Bulkeley said making the call was regrettable, but player safety had to take priority.

"This decision has not been taken lightly as we are aware of all the work and anticipation that has gone into this weekend," Bulkeley said.

"But we have a duty of care for all players and officials; this must be paramount."

Fears over the synthetic turf absorbing heat at a more rapid rate than grass pitches warranted the decision.

Bulkeley said after consultation, FT had found the onfield temperature could rise up to the mid-to-high 40s, representing a clear danger to the wellbeing of players.

"Football Tasmania has consulted with other states' governing bodies in arriving at this decision, especially those [states] where this kind of weather is a more common occurrence," he said.

"The action of postponing or changing kick-off times is a consistent step that is taken when extreme hot weather is predicted. With this in mind, we believe this is the most prudent step for us to take."

Riverside NPL coach Alex Gaetani admitted the shock postponement was a blow to the club's preparations.

The Roos will now prepare to host respective rookies Glenorchy Knights instead.

"We were excited to play this weekend - we were very much ready," Gaetani said.

"We have been preparing for round one for a long time.

"But our first round is next week now."

But Gaetani backed in the eleventh-hour call after Football Tasmania considered switching games to Sunday.

"There is too much risk involved in playing at that kind of heat to players that could have a condition," he said.

The move from 21 to 27 rounds with two new sides forced FT to start the NPL Tasmania season earlier.

But Gaetani said his side was embracing the extended campaign this year.

"The season starting a little bit earlier meant this was a possibility," he said.

"But it's good that the season has started earlier.

"The more football our players and the NPL get to play the better."

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