The National Capital Commission is reminding the city that building light rail transit on the Ottawa River Parkway is not a done deal.

"(City officials) have been told numerous times, don't assume it's the cheapest way and don't assume it's the easiest way," NCC CEO Marie Lemay said Wednesday.

The western portion of the Ottawa River Parkway is one of three options for extending the city's light rail transit plan to the west.

The other options would involve light rail on either Byron Avenue or Carling Avenue.

An ongoing environmental assessment will explore all three options. The NCC says even after that's complete, nothing is guaranteed.

"Before you can do anything on federal land, it has to be a last resort. It has to be a very compelling and powerful reason," said Lemay.

While the NCC is cool to the idea of having light rail on the parkway, the board approved plans Wednesday that would allow light rail transit between Blair Road and Tunney's Pasture.

With a report from CTV Ottawa's John Hua