SYDNEY, July 29 (Reuters) - Australian Prime Minister Scott Morrison said vaccinations alone would not bring an end to a COVID-19 lockdown in Sydney as residents of the country"s largest city face another month under tough curbs to stamp out an outbreak of the Delta variant. "I mean, it can certainly help ... the low rates (of vaccination) we have had there need to lift and that will certainly help the efforts with the lockdown but on its own it won"t stop the lockdown," Morrison told Nine News on Thursday. Morrison hoped the extended lockdown and tougher curbs on movement enforced in the worst affected regions of Sydney could contain the "incredibly virulent" Delta variant. read more With only about 17% of people above 16 years fully vaccinated in New South Wales state, which Sydney is the capital of, infections have steadily risen despite Greater Sydney being in lockdown since June 26. More than 2,500 cases have been detected so far in the state"s worst outbreak of this year, with 165 people hospitalised. Fifty-six are in intensive care, 22 of whom require ventilation. "What we have seen are stubborn numbers ... we are not going to pretend that we have every answer because we don"t," State Deputy Premier John Barilaro told Nine News. A total of 177 cases were detected, most of them in state capital Sydney on Wednesday - the biggest daily rise since March 2020. Greater Sydney"s extended lockdown of around 6 million people is expected to take a heavy toll on Australia"s A$2 trillion ($1.50 trillion) economy with many businesses forced to close, raising prospects of the country recording its second recession in as many years. Federal Treasurer Josh Frydenberg said he expected the national economy to shrink in the September quarter but hoped Australia could avoid a recession if New South Wales suppress the outbreak soon. "With respect to the December quarter, that does depend to a large extent how successful New South Wales, our largest state economy, is in getting on top of this virus," Frydenberg told the Australian Broadcasting Corp. ($1 = 1.3561 Australian dollars)