With Canberra's triathlon season beginning this weekend, and the first Triathlon ACT-sanctioned event set for the following Sunday, November 25, the ACT government has given conditional approval for Belconnen's Lake Ginninderra to be used as a back-up site for events.

Triathlon ACT's primary site is Lake Burley Griffin, but the poor water quality due to algae and bacterial issues has often forced the late cancellation of the swim leg.

It has been a major source of frustration for athletes - particularly those who have registered in advance and travelled from interstate.

Acting general manager of Triathlon ACT Sarah Mareuil said the contingency plan of Lake Ginninderra, approved by Roads ACT, would allow the sport to better market itself for its bigger events.

This season Canberra will host the Australian Sprint Championships on January 27 and an Olympic distance world championship qualifying event on March 2.

''We are going to be able to deliver what we are selling,'' Mareuil said.

''Especially for national events, when we are attracting people from other states, then we say it's going to be a duathlon instead of a triathlon [because Lake Burley Griffin is closed] it's a massive disappointment for people.

''We received a couple of comments from people saying they didn't want to race in Canberra any more because they didn't know if they were going to race a triathlon or a duathlon, so they preferred other events elsewhere … this is a great relief.''

At this stage the Lake Ginninderra contingency plan has only been approved for the opening event of the Triathlon ACT calendar, next Sunday's event. But it is expected to be extended for Triathlon ACT's other races.

Organisers of the Sri Chinmoy Triathlon festival hope their iconic long distance Peace Triathlon is not lost forever.

The 30th edition of the Sri Chinmoy Triathlon festival will be held in Canberra this weekend, with more than 500 participants registered for the four events.

But for the first time in the festival's history, it will not include the headline event, the Peace Triathlon - a 2.2-kilometre swim, 80km cycle and 20km run.

At its peak, the Peace Triathlon alone attracted a field of up to 1200 triathletes, but declining interest has forced its cancellation this year.

''It's a far cry from what it was in those days … last year we only had about 40 entrants in it,'' organiser Prachar Stegemann said.

''We're definitely open to bringing it back, not this year or probably next year, but it holds a special place in our heart.

''It's just a matter of getting the support from athletes to make it viable, really.''

Organisers have been forced to modify the bike course for the Canberra 70.3 Triathlon in December due to protracted roadworks on Cotter Road which they say created a ''dangerous situation for bikes''.

The new course will speed up times, with participants no longer having to climb the steep hills along Coppins Crossing.