The Spaniard was subjected to questions about his long-term future as early as the first pre-season test of 2016, but he told media in Azerbaijan - he is an ambassador for the country's inaugural F1 race in Baku - that he will wait until 2017 before making any decision.
"I have a contract until the end of 2017, so that's the minimum I will be [at McLaren]," said Alonso, who also conducted a track walk of the new Baku City Circuit.
"Then in 2017 the regulations will change a lot, the cars will be very different - supposed to be five-seconds faster. So I will drive in 2017, see how much I enjoy driving those cars, and I will make a decision to stay more years or to stop in F1."
Asked about his prospects for the coming season, Alonso said McLaren 'must' challenge for points at every race, and push for the podium in the second half of the season - but admitted they have a lot to do before to reach that position.
"For this year the goal is to be often in the points - we must be every race in the points, and then fighting for podiums in the second part of the season," he explained.
"We are happy with the starting point, but we know all our competitors are also quite strong so we need to work hard. We are in a better position [compared to 2015] but not where we wanted; we are not that strong right now, but we know what we need to change."
The deadline for completing Formula One's 2017 Sporting and Technical Regulations was recently extended to 30 April in order to allow all stakeholders the best opportunity to finalise all relevant work - especially with regard to power unit regulations focusing on the four key areas of supply cost, obligation to supply, performance convergence, and further improvement of noise.