Venezuela's supreme court has struck down an attempt by the opposition to cut short President Nicolas Maduros' term in office, ruling that a proposed constitutional amendment to that effect cannot be applied retroactively.

Venezuela's opposition won control of the legislature last year and is seeking to remove Maduro, proposing both a recall referendum and an amendment to cut his term from six to four years. Maduro is near the mid-point of his presidency.

The constitutional amendment will be submitted to a second debate in the legislature in the coming days, but even before its final approval the court has weighed in to rule that the move would be constitutional if approved by a referendum but could not be applied to Maduro's term.

It "cannot take effect retroactively or be applied immediately," the court said.

The socialist Maduro has seen his popularity plummet amid a recession, high inflation and product shortages.