July 19 (Reuters) - Office space provider IWG (IWG.L) is set to open eight new shared-office centres in locations including London and New York, five of which were previously operated by its U.S.-based rival WeWork, as it seeks to meet the growing need for flexible work spaces. Two of the former WeWork properties are located in Kensington, London, and Park Avenue South, New York, with three more in the Indonesian capital, Jakarta. The other sites are in Chicago, Philadelphia, and opposite Penn Station in New York, according to a statement exclusively seen by Reuters. IWC, owner of the Spaces and Regus brands, has said demand for such sites was up 14% in June from pre-pandemic levels. It will invest in refurbishing the properties. IWG, which has its head office in Switzerland and more than 3,300 locations across 110 countries, added over 100 centres in the first half of 2021 through its franchise partners, three times as many as in the first half of 2020. read more After a year in which the coronavirus pandemic shut office buildings and forced people to work from home, companies around the world are reducing their office space with an eye on trimming costs. "The pandemic has accelerated the shift to the hybrid model by 10 years ... There has been a rapid change," said Mark Dixon, the boss of IWG. "Office spaces in cities like New York and London are going to shrink in a post-pandemic world as some people move back to towns and countryside. It is hard to quantify by how much." From U.S. tech giants Amazon (AMZN.O) and Microsoft (MSFT.O) to banks such as Standard Chartered (STAN.L), firms have announced plans to adopt some form of flexible working model, typically having staff work from home for part of the week. Dixon said there would be more change over the next three years as companies" leases end. "We are seeing a continuous interest in suburban and countryside locations as people avoid the commute and other hassles of a city life."