The plans, which have been submitted to Powys planners by CarneySweeney on behalf of Lidl to allow the store to accommodate the recycling of waste packaging, will mean the loss of 13 car parking spaces.
It comes ahead of expected laws requiring waste packaging to be recycled as part of a Deposit Return Scheme (DRS).
The plans involved changes to the rear area of the supermarket and car park. It will not affect the shop floorspace.
"The Government issued a Resource and Waste Strategy in 2018, which included the introduction of Deposit
Return Schemes (DRS) relating to the recycling of single use plastics" said a letter to planners with the application.
"DRS works by placing a small charge on the cost of an item of packaging, which is returned to a customer when the item is recycled via a dedicated recycling scheme. DRS schemes have been operational in mainland Europe for over a decade, notably, in Germany, where Lidl was founded.
"The DRS scheme for England and Wales is expected to be operational from late 2024."
It added: "The proposal is to create a DRS facility within the existing ground floor of the foodstore, in place of existing staff welfare facilities.
"This will involve internal layout changes and the creation of a glazed DRS customer lobby on the east elevation, adjacent to the store entrance.
"The staff welfare facilities are to be relocated and housed within an extension to the rear of the building, on the southern elevation. This requires an amendment to the loading bay and the loss of 13 standard car parking spaces.
Newtown Town Council's Economy and Environment Committee will discuss the plans before submitting any comments to Powys County Council's planning committee as part of the application process.