Commuters using Sydney's $2.9 billion light rail from next weekend will have to wait months before services are fully "bedded down" and reach their targeted frequency of up to one every four minutes.

Despite four years of delays, cost blowouts and construction disruption, Transport Minister Andrew Constance has urged people to consider the project's "big picture outcome" and remember the conga lines of buses along George Street before the light rail build began.

"The pain is absolutely worth it – the city has changed forever," he said.

"It has been one of the most complex and difficult projects but it is going to produce an incredible outcome. We went through a period where everybody lost some skin on the project but we ensured it was delivered in 2019."